On-board computers are assuming more and more of the tasks associated with running automobiles. A the complexity of the computers and of the tasks have increased, so has the difficulty of insuring the proper operation of the computers. this is due in part to the fact that the response of a computer may be a function, not only of the computer's immediate inputs, but a history of the computer's inputs and bus states. Thus, in analyzing a particular computer response, it is often useful to know certain of the computer's prior inputs and bus states.
Although logic analyzers, such as the logic analyzer which is designated 1631A/D by Hewlett-Packard Inc., are of use in recording the bus states of computers, such analyzers are less than ideally suited for long term, dedicated, monitoring of on-board computers.
Also, although the system which is referred to as a Flight Recorder by the Grid Corporation is designed for long term monitoring of on-board computers, the system lacks the means necessary to provide critical information.